Handle Ruby 2.7 syntax (prettier#458)

CHANGELOG.md

@@ -6,6 +6,22 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/) a
 
 ## [Unreleased]
 
+### Added
+
+- Support for the `nokw_param` node for specifying when methods should no accept keywords, as in:
+
+```ruby
+def foo(**nil); end
+```
+
+- Support for the `args_forward` node for forwarding all types of arguments, as in:
+
+```ruby
+def foo(...)
+  bar(...)
+end
+```
+
 ## [0.17.0] - 2019-12-12
 
 ### Added

src/nodes/args.js

@@ -17,6 +17,13 @@ module.exports = {
       return "";
     }
 
+    // Here we can skip the entire rest of the method by just checking if it's
+    // an args_forward node, as we're guaranteed that there are no other arg
+    // nodes.
+    if (path.getValue().body[0].type === "args_forward") {
+      return "(...)";
+    }
+
     const { addTrailingCommas } = opts;
     const { args, heredocs } = makeArgs(path, opts, print, 0);
 

src/nodes/blocks.js

@@ -8,7 +8,7 @@ const {
   removeLines,
   softline
 } = require("../prettier");
-const { empty, first, hasAncestor } = require("../utils");
+const { empty, hasAncestor } = require("../utils");
 
 const printBlock = (path, opts, print) => {
   const [variables, statements] = path.getValue().body;
@@ -76,6 +76,5 @@ module.exports = {
   },
   brace_block: printBlock,
   do_block: printBlock,
-  excessed_comma: empty,
-  number_arg: first
+  excessed_comma: empty
 };

src/nodes/params.js

@@ -1,4 +1,5 @@
 const { concat, group, join, line } = require("../prettier");
+const { literal } = require("../utils");
 
 const printGenericRestParam = symbol => (path, opts, print) =>
   path.getValue().body[0]
@@ -53,7 +54,7 @@ const printParams = (path, opts, print) => {
   }
 
   if (kwargRest) {
-    parts.push(path.call(print, "body", 5));
+    parts.push(kwargRest === "nil" ? "**nil" : path.call(print, "body", 5));
   }
 
   if (block) {
@@ -79,6 +80,7 @@ const paramError = () => {
 };
 
 module.exports = {
+  args_forward: literal("..."),
   kwrest_param: printGenericRestParam("**"),
   rest_param: printGenericRestParam("*"),
   params: printParams,

src/ripper.rb

@@ -166,6 +166,7 @@ def find_scanner_event(type, body = :any)
         assoc_splat: [:@op, '**'],
         arg_paren: :@lparen,
         args_add_star: [:@op, '*'],
+        args_forward: [:@op, '...'],
         begin: [:@kw, 'begin'],
         blockarg: [:@op, '&'],
         brace_block: :@lbrace,

test/js/blocks.test.js

@@ -122,10 +122,6 @@ describe("blocks", () => {
 
     test("does not split up args inside pipes", () =>
       expect(`loop do |${long} = 1, a${long} = 2|\nend`).toMatchFormat());
-
-    if (process.env.RUBY_VERSION >= "2.7") {
-      test("number args", () => expect("loop { @1 * 2 }").toMatchFormat());
-    }
   });
 
   describe("to_proc transform", () => {

test/js/method.test.js

@@ -49,6 +49,20 @@ describe("method", () => {
       return expect(content).toMatchFormat();
     });
 
+    if (process.env.RUBY_VERSION >= "2.7") {
+      test("nokw_param", () => expect("def foo(**nil); end").toMatchFormat());
+
+      test("args_forward", () => {
+        const content = ruby(`
+          def foo(...)
+            bar(...)
+          end
+        `);
+
+        return expect(content).toMatchFormat();
+      });
+    }
+
     test("breaking", () =>
       expect(`def foo(${long}:, a${long}:); end`).toChangeFormat(
         ruby(`
@@ -171,11 +185,6 @@ describe("method", () => {
         expect("Foo::foo").toChangeFormat("Foo.foo"));
 
       test("lonely operator", () => expect("foo&.foo").toMatchFormat());
-
-      if (process.env.RUBY_VERSION >= "2.7") {
-        test("method reference operator", () =>
-          expect("foo.:foo").toMatchFormat());
-      }
     });
 
     describe("breaking", () => {

test/rb/metadata_test.rb

@@ -734,6 +734,20 @@ def test_zsuper
   end
 
   if Gem::Version.new(RUBY_VERSION) >= Gem::Version.new('2.7')
+    def test_args_forward
+      content = <<~RUBY
+        def foo(...)
+          bar(...)
+        end
+      RUBY
+
+      assert_node_metadata(
+        :args_forward,
+        parse(content).dig(:body, 1, :body, 0, :body, 2),
+        char_start: 8, char_end: 11
+      )
+    end
+
     def test_aryptn
       content = <<~RUBY
         case foo